1. Field of the Invention
The present invention relates to a device for controlling the thread lever of a braiding machine comprised of the combination of a circular ring-shaped, closed curved path and correlated sliding block, wherein the thread lever has a pivot axle which is connected above the lower feed bobbins to the gear housing, which is rotatingly driven in a first rotational direction about the central pipe of the braiding machine, wherein the thread lever describes as a result of the rotational movement of the gear housing a rotational plane and, by means of the sliding block, is imparted with an oscillating pivot movement about its pivot axle in this rotational plane, and wherein the rotational movement of the gear housing is transformed into a second rotational direction opposite to the first rotational direction via a reversing gear with intermediate wheel and is then imparted onto the bobbin carriers of the warp thread bobbins. The present invention further relates to a braiding machine with a central pipe and a housing rotatingly driven about the central pipe in a first rotational direction, on which bobbin carriers for the lower feed bobbins are seated as well as with upper bobbin carriers for the upper feed bobbins which are also rotatably supported to rotate about the central pipe, wherein between the lower feed bobbins and the upper feed bobbins a positive-locking reversing gear with intermediate wheel is provided which at the input side is loaded by the rotational direction of the housing and at the output side generates the second rotational direction opposite to the first rotational direction with which the upper bobbin carriers of the upper feed bobbins are loaded.
2. Description of the Related Art
Such braiding machines are known; see, for example, the catalog of Spirka xe2x80x9cSpirka-Schnellflechterxe2x80x9d. These rapid braiders, according to the catalog, allow rotational speeds up to approximately 150 per minute, depending on the number of bobbin groups rotating in opposite directions, respectively.
The plurality of required gear couplings and kinematic parameters make it difficult to increase this rotational speed at will.
One of the decisive parameters of a braiding machine is the rotational speed limit. It depends on several factors, i.e., the type of control of the thread lever and/or the type of gear coupling between the drive members, the reversing gear, and the bobbin carriers.
The thread lever, on the one hand, must be pivotably supported above the weft thread bobbins, and, on the other hand, below the warp thread bobbins.
In this connection, the upper end of the thread lever must project past the warp thread bobbins to such an extent that the corresponding weft thread can be received by a thread guide which defines the movement plane of the weft thread above the warp thread.
Conventionally, the control of the thread lever results from a combination of a circular ring-shaped, closed curved path with corresponding sliding block. The curved path is arranged outside of the rotation plane on which the thread lever circulates during rotation of the weft thread bobbins.
The curved path thus encompasses the entire braiding machine.
However, since the thread lever has a relatively great length, relatively high moments of inertia are to be expected which must be exerted as forces by the sliding path pairxe2x80x94comprised of the sliding block and the curved pathxe2x80x94in order to impart onto the thread lever its fast pivot movement. The relatively large spacing of the curved path from the center of rotation moreover effects relatively high relative speeds between the sliding block and the curved path so that relatively high surface pressures are to be expected in this connection.
On the other hand, the reversing gear of braiding machines with central pipes is an important component in order to impart onto the upper bobbin carriers a rotational movement about the central pipe opposite to that of the lower bobbin carriers.
Since these mechanical gears contribute significantly to the power requirements of a braiding machine, there is always the tendency to use gears with minimal consumption of power.
However, this causes the problem that, in addition to a reversal of the rotational direction between lower thread bobbins and upper thread bobbins, also a predetermined ratio of transmission must be maintained which is prescribed by the braiding process.
It is therefore the object of the present invention to improve the braiding machine such that higher rotational speeds are enabled.
On the one hand, this object is solved by the invention in regard to the device for controlling the thread lever in that the sliding block and the curved path are located within the rotational plane, and, on the other hand, in regard to the braiding machine in that the reversing gear comprises an internal ring gear stationarily arranged on the central pipe with a large reference diameter, a pinion revolving therein, and an external ring gear with small reference diameter rotatably supported on the central pipe, and wherein the revolving pinion is rotatably supported on a revolving axle fixedly connected with the housing as well as provides the positive-locking connection between the internal ring gear and the external ring gear.
There are therefore two different measures with which the rotational speed limit of such braiding machines can be increased.
These measures can be realized independently from one another and also in combination with one another on a single braiding machine.
In the following, the inventive measures of the device for controlling the thread lever will be discussed first.
This part of the invention results in the advantage that for a more compact configuration of the braiding machine the weft thread bobbins and the warp thread bobbins become more easily accessible.
This advantage is achieved in that the previously known enclosure of the braiding machine by the stationary curved path is eliminated and replaced with an inwardly displaced curved path; this facilitates access to the weft thread bobbins and the warp thread bobbins.
An important factor of this part of the invention is that the sliding block and the curved path are positioned within the rotational plane which is described by the thread lever upon its rotation about the central pipe of the braiding machine.
On this rotational plane the thread lever additionally carries out the pivot movement which results in the braiding of the warp threads and the weft threads.
With this part of the invention, on the one hand, the relative speed between the sliding block and the curved path is reduced, because the engagement circle between the sliding block and the curved path is on a smaller radius in comparison to a curved path arranged outside of the rotational circle.
Since the law of movement of the thread lever, moreover, is defined by the curvature of the so-called thread guide, the exact geometric shape of the curved path results automatically so that the weft thread traverses up and down with constant contact on the thread guide.
The more the engagement circle between the curved path and the sliding block is moved toward the central axis of the braiding machine, the smaller the relative speeds, without the predetermined law of movement of the thread lever being negatively affected. In this respect, it is desirable to position the engagement circle between the sliding block and the curved path within the circle which is described by the inner end of the pivot axle. This provides the additional possibility of positioning the pivot axle of the thread lever in a bore of the gear housing where the sliding block and the curved path can be positioned in an oil bath.
With the permanent oil lubrication enabled in this way, relative speeds between the sliding block and the curved path which have been unattainable previously should be permissible.
For simplifying the configuration, the curved path can be arranged on an annular console which is connected as a separate component stationarily to the central pipe.
Moreover, the pivot axle can be positioned at a slant such that it is inclined with its end facing the central pipe toward the braiding point. This practically means the exit end of the material to receive the braid from the central pipe. This enables an effective pivot movement above the warp thread bobbins and below the warp thread bobbins with minimal forces. The decisive limit anglexe2x80x94measured relative to the normal plane of the central axisxe2x80x94is 45 degrees. This results in a permissible angle range of 45xc2x0 greater than alpha greater than 0xc2x0.
When the curved path is then inclined additionally about an angle L like the pivot axle, an excellent surface contact between the sliding block and the curved path results.
In order to compensate moreover tension fluctuations which result upon pivoting of the thread lever, a thread buffer roll is additionally provided which serves for a temporary thread deposition of the weft thread upon pivoting in the sense that the weft thread tension is practically maintained constant.
From the additional dependent claims advantageous embodiments of the invention result. The second part of the invention has the advantage that the housing for receiving the gear of the braiding machine can be configured significantly smaller and more compact so that in this way also an excellent accessibility to the weft thread bobbins and the warp thread bobbins is ensured.
With the compact configuration of the housing, the resonance behavior of the braiding machine is favorably affected, and the rotational speed limit can thus be increased. In principle, this part of the invention is based on the reversing effect which is caused by the pinion revolving within the internal ring gear. The internal ring gear is stationary; the pinion circulating in its interior is supported at its engagement location with the external ring gear with smaller reference diameter on the output side of the gear, and the reversal of the rotational direction is caused in this way.
At the same time, this planet wheel arrangement enables the adjustment of the required rotational speed ratios which are required for the braiding process.
However, the special advantage of this part of the invention resides also particularly in its independence from the measures in regard to the device for controlling the thread lever.
Even though, this part of the invention can be used in combination with the features of the device for controlling the thread lever.